Rule one:Idghaam Shafawee (Lip-based Merging or Merging with the use of lips).

For any meem saakinah, when a second meem follows it, Idghaam Shafawee is sounded for two counts, i.e. the time it takes to say the words, “one – two”. The condition here is that the latter meem has a fat-ha, dammah or kasra on it. Note a shaddah on the second meem is drawn as a notice of this rule [i.e. it is not there for shaddah purposes].